[Corneal biomechanics before and after cross-linking in patients with keratoconus]. / Die Biomechanik der Hornhaut vor und nach Crosslinking bei Patienten mit Keratokonus.

OBJECTIVE: The aim of this study was to analyze the effect of corneal cross-linking (CXL) on corneal biomechanics and visual acuity. PATIENTS AND METHODS: The examination results before and after CXL in 56 eyes of 56 patients between 2017 and 2021 were evaluated retrospectively. The last preoperative examination was compared to the postoperative follow-up values after 6 and 12 months. The main outcome measures included various biomechanical parameters from the Corvis ST (CST), Pentacam and the visual acuity (logMAR, "logarithm of the Minimal Angle of Resolution"). For longitudinal evaluation, a general linear model for repeated measurements was used. A p-value of less than 0.05 was considered to show a statistically significant result. Bonferroni correction was applied for multiple comparisons. RESULTS: The maximum corneal refractive power Kmax decreased slightly without statistical significance from 57.1 ± 6.1 diopters (dpt) to 56.6 ± 6.3 dpt after 6 months (p = 0.076) and 56.8 ± 6.6 dpt after 12 months (p = 0.443). The Pentacam parameter Belin/Ambrósio Enhanced Ectasia Total Deviation Display (BAD D) showed a statistically significant increase from the preoperative value of 8.4 ± 3.7 to the postoperative value of 9.1 ± 3.6 after 6 months (p < 0.001) and to 8.9 ± 3.5 after 12 months (p = 0.051). The CST parameter Ambrósio's relational thickness to horizontal profile (ARTh) decreased statistically significantly from 229.9 ± 109.6 to 204.8 ± 84.9 at 6 months (p = 0.017) and 205.3 ± 93.7 at 12 months (p = 0.022). The CST parameter stiffness parameter A1 (SP A1) increased slightly from the preoperative value 69.9 ± 17.2 to 70.4 ± 17.2 after 6 months (p = 1) and 71 ± 18.2 after 1 year (p = 1). Mean best-corrected visual acuity (logMAR) showed an improvement from 0.39 ± 0.3 to 0.34 ± 0.3 at 6 months (p = 0.286) and to 0.31 ± 0.3 at 12 months (p = 0.077). Regarding the ABCD classification, the parameters were determined preoperatively with an average of A2B3C1D2. They showed the same value of A2B3C1D2 after 6 and 12 months. CONCLUSION: In progressive keratoconus, corneal cross-linking has the potential to positively influence the biomechanics of the cornea and visual acuity as a low complication treatment option.

[Immune reaction after penetrating keratoplasty depending on graft size and centration]. / Immunreaktion nach perforierender Keratoplastik in Abhängigkeit von der Transplantatgröße und -zentrierung.

BACKGROUND: Immune reaction (IR) after penetrating keratoplasty (PKP) is a serious complication with a high risk of graft failure. The aim of this study was to analyze and evaluate the risk factors for IR, in particular, the influence of graft size and centration. PATIENTS AND METHODS: A total of 2133 patients who underwent PKP between January 2009 and July 2019 were included in this retrospective study. The following endpoints were analyzed: frequency of IR, graft origin, donor and patient age, diagnosis, corneal diameter and ratio of the graft size to the recipient cornea size. In addition, the role of graft centration, with the help of distance measurements of the graft margins to the vascularized limbus at four locations, was investigated in detail. RESULTS: Overall, 8.25% of patients suffered from IR during the observational period. The frequency of IR was significantly correlated (p < 0.001) with the ratio of the graft size to the recipient cornea size. In addition, a statistically significant correlation was found between the occurrence of IR and a small distance to the limbal margins in the Y­axis (inferior and superior). In particular, the correlation coefficient was larger at the inferior limbus (p < 0.001). CONCLUSION: An IR after PKP is a not uncommon complication and is significantly related to graft size and centration. A large graft chosen in relation to the recipient cornea and the proximity of the graft to the vascularized limbus at the inferior and superior sites significantly correlate with the occurrence of IR. These are important risk factors for graft survival, which can be influenced by the corneal microsurgeon and could possibly be further optimized in the future.

[Phototherapeutic keratectomy for epithelial basement membrane dystrophy : Impact of excimer laser systems used on the changes of visual acuity, refraction and astigmatism]. / Phototherapeutische Keratektomie bei Epithel-Basalmembran-Dystrophie : Einfluss verwendeter Excimerlaser-Systeme auf die Entwicklung von Visus, Refraktion und Astigmatismus.

BACKGROUND: Excimer laser-assisted phototherapeutic keratectomy (PTK) has become established as the gold standard in treatment of epithelial basement membrane dystrophy (EBMD), commonly also known as map-dot-fingerprint dystrophy (MDF). At the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar, systems from Zeiss Meditec and Schwind have been used. The outcomes of both were compared in this study. PATIENTS AND METHODS: The retrospective study included patients who underwent PTK with a diagnosis of MDF between 2007 and 2017. A total of 170 operations were performed using Zeiss Meditec MEL-70 (Carl Zeiss Meditec AG, Jena, Germany) and 98 using a Schwind eye-tech-solutions Amaris 750S laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany). Preoperative and postoperative data for visual acuity, refraction and astigmatism as well as curvature data from the Pentacam and endothelial cell count were collected. The follow-up period averaged 8 months. RESULTS: In both groups visual acuity postoperatively was significantly better (Zeiss: p < 0.001, Schwind p < 0.004). The improvement in the Schwind group was less than in the Zeiss group, which is the reason why there was a significant difference between the laser systems postoperatively (p < 0.017). There were no significant changes regarding the spherical equivalent after PTK. Regarding astigmatism, there was a significant decrease in the Zeiss group (p < 0.042), while it did not change significantly in patients treated with Schwind laser (p < 0.217). Overall, this led to a significant postoperative difference between both laser systems (p < 0.014). CONCLUSION: The PTK can be recommended as an effective treatment method for patients with EBMD, regardless of the laser systems used. Patients benefit from long relief from recurrences with improved or constant visual acuity and stable refraction.

[Partial visual rehabilitation 5 and 6 years after a Gundersen total conjunctival flap procedure]. / Partielle visuelle Rehabilitation 5 und 6 Jahre nach totaler Bindehautdeckung mittels Gundersen-Flap.

BACKGROUND: We present the results of penetrating keratoplasty (PKP) after previous treatment with a total conjunctival flap in two patients. CASE REPORTS: Patient 1, a 66-year-old with a history of bilateral cement chemical burn in 1986 and external right-sided limbokeratoplasty in 2008 was treated externally with a total conjunctival flap in the right eye in 2014 due to a persistent corneal ulcer with imminent perforation. Best-corrected visual acuity (BCVA) in the right eye was light sensation, intraocular pressure on palpation was within normal range. Clinically, total conjunctival flap was present. Patient 2 was treated externally in May 2015 due to acanthamoeba keratitis in the left eye with a deep anterior lamellar keratoplasty (DALK). A re-DALK was also performed externally in the same month. A third DALK was performed externally in August 2015 due to a persistent corneal ulcer, followed by a total conjunctival flap 2 weeks later. BCVA of the left eye was light sensation and intraocular pressure on palpation was within the normal range. RESULTS: Patient 1 was treated with removal of the conjunctival flap in the right eye and penetrating central re-keratoplasty (hand-held Barron trephine; graft diameter 8.5/8.75 mm). Simultaneously, lens extraction and intraocular lens implantation were performed (as a triple procedure). Additionally, amniotic membrane transplantation (AMT) as patch and a temporal lateral tarsorrhaphy were performed. BCVA 6 months postoperatively was 0.1. The graft was clear, without any signs of rejection. Patient 2 was treated on the left eye with removal of the conjunctival flap and a penetrating central keratoplasty (hand-held Barron trephine; graft diameter 7.0/7.5 mm). An AMT as patch and a temporal lateral tarsorrhaphy were simultaneously performed. Cataract surgery was performed 3 months postoperatively and BCVA of the right eye was 0.1 thereafter. The graft was clear, without any signs of rejection. CONCLUSION: The conjunctival flap is a treatment of last resort of the (almost) penetrated corneal ulcer, which is to be used only when a keratoplasty is technically impossible. Provided the eye structure and retinal function are preserved, partial visual rehabilitation can possibly be achieved through a PKP after excision of the conjunctival flap, even years after corneal blindness.

Sonographic and ophthalmic assessment of optic nerve in patients with idiopathic intracranial hypertension: A longitudinal study.

BACKGROUND: To assess the validity of neurosonological parameters (transorbital sonography (TOS)) for detection and monitoring of patients with idiopathic intracranial hypertension (IIH). METHODS: Prospective, single-center, case-controlled study in 25 patients with IIH and 19 controls. Visual parameters of papilledema, visual acuity, computerized static threshold perimetry, fundus examination, and neurosonological parameters of papilledema/optic disc elevation (ODE), optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) were recorded at baseline and only for patients with IIH again within 6 months. RESULTS: ONSD was significantly enlarged among individuals with IIH (6.2 ± 0.73 mm) compared to controls (4.99 ± 0.54 mm; p < 0.001). Bilateral ODE was found in 36/50 eyes in patients at their initial visit and in none of the controls. Re-evaluation 6 months later showed a significant reduction of ONSD (6.0 ± 0.7 mm; p = 0.024) and ODE (0.2 (0-1) mm; p ≤0.001). Best corrected visual acuity (BCVA) and square root of lost variance (sLV) remained stable. Headache intensity (Numeric rating scale, NRS) improved significantly p < 0.001. When compared to patients with first diagnosed IIH (n = 18), the subset of patients with preexisting IIH with acute relapse (n = 7) showed persistent but reduced levels of ICP increase. They also presented significant decrease of BVCA (p = 0.01) and mean defect (MD) (p = 0.012). Re-evaluation 6 months later showed significant change in ODE in both groups. CONCLUSIONS: Our study confirmed that TOS and ophthalmological parameters are a valuable and non-invasive method to detect and monitor elevated ICP in IIH.

An attempt to optimize the outcome of penetrating keratoplasty in congenital aniridia-associated keratopathy (AAK).

PURPOSE: To propose an optimized microsurgical and medical approach to reduce the risk of complications after penetrating keratoplasty (PKP) in patients with aniridia-associated keratopathy (AAK). METHODS: Retrospective observational case series of 25 PKP performed in 16 patients with AAK. Preoperative indications were endothelial decompensation and vascularized scars (68%) or graft failure (32%) due to limbal stem cell deficiency. The optimized approach included a combination of a small corneal graft size (around 7.0 mm), interrupted 10-0nylon sutures, simultaneous AMT as a patch, large bandage contact lens, temporary lateral tarsorrhaphy, postoperative autologous serum eye drops, and systemic immunosuppression. Main outcome measures included: visual acuity, transplant survival, and complications encountered during follow-up of 107 weeks on average. RESULTS: A complete modified keratoplasty scheme was used in 10 of 25 PKP (group 1), while at least one of the modifications was missing in the other 15 PKP (group 2). After 8 weeks of follow-up, the epithelium was closed in 23 eyes. Visual acuity improved in 19 eyes at 6 months of follow-up, and remained stable in six eyes. None of the eyes showed a decrease in visual acuity. At the last post-operative follow-up, this visual improvement persisted in 14 eyes and graft survival rate after 156 weeks (3 years) was 69% in group 1 versus 44% in group 2 (p = 0.39, log-rank test). Secondary corneal neovascularization (8%), scarring (4%), ulcer (4%), or graft rejection (8%) happened mostly in the second group which was missing at least one of the suggested modifications. CONCLUSIONS: PKP in congenital aniridia must be considered as a high-risk keratoplasty. An optimized therapeutic approach seems to be promising in order to reduce the postoperative complication rate in these most difficult eyes.

[Stage-appropriate treatment of keratoconus]. / Stadiengerechte Therapie des Keratokonus.

Keratoconus (KC) is a progressive cone-shaped corneal protrusion that causes paracentral thinning at the apex of the cone and typically occurs asymmetrically on both sides. After a careful anamnesis and classification of the degree of severity a targeted treatment appropriate to the stage of the disease is available. If the visual acuity is no longer sufficient, rigid gas-permeable contact lenses (CL) are fitted by a specialist. Riboflavin UVA cross-linking (CXL) is recommended in cases of progression and visual acuity that is still useful for the patient. Intracorneal ring segments (ICRS) are indicated for CL intolerance in cases of reduced visual acuity and a clear central cornea. If the stage is more advanced, deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PKP) is recommended. A PKP is contraindicated in acute KC but deep stromal sutures for readaptation of the Descemet tear with gas filling of the anterior chamber can considerably shorten the course. Almost no other eye disease is nowadays as easily accessible for an early instrument-based diagnosis and stage-appropriate treatment as KC.

[Coinfections in contact lens-associated mycotic keratitis with Pseudomonas or Acanthamoeba]. / Mischinfektionen bei kontaktlinsenassoziierter mykotischer Keratitis mit Pseudomonas oder Akanthamöben.

Contact lens-associated keratitis is becoming increasingly more frequent. Fungal keratitis is a relatively rare clinical picture but must be taken very seriously. Especially in the early stages of the disease, it may be clinically misdiagnosed and adequate treatment is therefore delayed. In treatment-resistant contact lens-associated fungal keratitis, coinfections or superinfections can occur. We present two patients with an initially unclear keratitis, in whom a fungal keratitis with coinfection of Pseudomonas aeruginosa and Acanthamoeba, respectively, could be confirmed. In both cases an urgent excimer laser penetrating keratoplasty with interrupted sutures and adequate local topical treatment for 8 weeks was successful.